(a) Field of the Invention
This invention relates to 2-alkoxy-5-(pyridinyl)pyridines and cardiotonic use thereof.
(b) Description of the Prior Art
Baker et al. [Drug Metab. Dispos., Vol. 10, No. 2, pp. 168-172 (1982)] show, inter. alia, 6-methoxy-(3,4'-bipyridin)-5-amine, alternatively named 3-amino-2-methoxy-5-(4-pyridinyl)pyridine.
P. Nantka-Namirski et al. [Pol. J. Pharmacol. Pharm. 30, No. 5, pp. 707-712 (1978)] in a paper entitled "Cancerostatics III. Synthesis and Some Chemical Transformations of 3-cyano-5-(pyridyl-4-)pyrid-2-one" show, inter alia, the reaction of 3-dimethylamino-2-(4-pyridinyl)acrolein with malononitrile and sodium methoxide in methanol at room temperature to produce 3-cyano-2-methoxy-5-(4-pyridinyl)pyridine. Also shown in this paper is 2-chloro-3-cyano-5-(4-pyridinyl)pyridine, disclosed in the instant application as an intermediate to prepare 3-cyano-2-methoxy-5-(4-pyridinyl)pyridine.
Singh [U.S. Pat. No. 4,347,363, issued Aug. 31, 1982] shows the reaction of pyridinylmethyl lower-alkyl ketone with ethoxymethylenemalononitrile in a lower-alkanol, e.g., ethanol, to produce 1,2-dihydro-6-methyl-2-oxo-5-(pyridinyl)nicotinonitrile, alternatively named 3-cyano-6-methyl-5-(pyridinyl)-2(1H)-pyridinone.
Shen et al. [U.S. Pat. No. 3,655,679, issued Apr. 11, 1972] show, inter alia, the reaction of 2-arylacetoacetaldehyde with ethyl cyanoacetate in methanol in the presence of piperidine to produce methyl 5-aryl-2-hydroxy-6-methylnicotinate, where aryl is phenyl or substituted-phenyl.
Lesher, Opalka and Page [U.S. Pat. No. 4,312,875, issued Jan. 26, 1982] show, inter alia, as cardiotonic agents 5-(pyridinyl-6-(lower-alkyl)-2(1H)-pyridinones and corresponding lower-alkyl 1,2-dihydro-5-(pyridinyl)-2-oxo-6-(lower-alkyl)nicotinates.